// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef BASE_MEMORY_MEMORY_PRESSURE_MONITOR_MAC_H_
#define BASE_MEMORY_MEMORY_PRESSURE_MONITOR_MAC_H_

#include <dispatch/dispatch.h>

#include "base/base_export.h"
#include "base/macros.h"
#include "base/memory/memory_pressure_listener.h"
#include "base/memory/memory_pressure_monitor.h"

// The following was added to <dispatch/source.h> after 10.8.
// TODO(shrike): Remove the DISPATCH_MEMORYPRESSURE_NORMAL ifndef once builders
// reach 10.9 or higher.
#ifndef DISPATCH_MEMORYPRESSURE_NORMAL

#define DISPATCH_MEMORYPRESSURE_NORMAL 0x01
#define DISPATCH_MEMORYPRESSURE_WARN 0x02
#define DISPATCH_MEMORYPRESSURE_CRITICAL 0x04

#endif // DISPATCH_MEMORYPRESSURE_NORMAL

namespace base {
namespace mac {

    class TestMemoryPressureMonitor;

    struct DispatchSourceSDeleter {
        void operator()(dispatch_source_s* ptr)
        {
            dispatch_source_cancel(ptr);
            dispatch_release(ptr);
        }
    };

    // Declares the interface for the Mac MemoryPressureMonitor, which reports
    // memory pressure events and status.
    class BASE_EXPORT MemoryPressureMonitor : public base::MemoryPressureMonitor {
    public:
        MemoryPressureMonitor();
        ~MemoryPressureMonitor() override;

        // Returns the currently-observed memory pressure.
        MemoryPressureLevel GetCurrentPressureLevel() const override;

    private:
        friend TestMemoryPressureMonitor;

        static MemoryPressureLevel
        MemoryPressureLevelForMacMemoryPressure(int mac_memory_pressure);
        static void NotifyMemoryPressureChanged(dispatch_source_s* event_source);

        std::unique_ptr<dispatch_source_s, DispatchSourceSDeleter>
            memory_level_event_source_;

        DISALLOW_COPY_AND_ASSIGN(MemoryPressureMonitor);
    };

} // namespace mac
} // namespace base

#endif // BASE_MEMORY_MEMORY_PRESSURE_MONITOR_MAC_H_
